Black tea is generally prepared by subjecting green tea leaves to various process conditions such as withering, rolling, disintegrating, fermenting, firing etc., during which enzymatic reactions are initiated in the tea leaves and the characteristic aroma, colour and flavour of black tea are developed. Black tea extract is produced by treating black tea leaves with warm water. The extract produced contain soluble tea solids as well as insoluble solids. The insoluble solids are discarded and the supernatant is processed further to recover any left over desirable tea properties such as flavor, aroma etc.
The characteristic feature of tea depends on the quantity and type of polyphenols present in tea, which make up of 20-35% of total dry weight of freshly plucked leaves. Approximately 70% of the polyphenols in the tea leaves are fermentable and take part in the chemical changes that take place during tea manufacture. The most important of the polyphenols, as far as quality of tea goes, are the epi-gallo catechin and gallates.
The supernatant left after removal of tea solids is concentrated, dried and sold as powder. Such a powder may be instantly soluble in hot water or cold water, as the case may be. This generally is the traditional method of tea manufacture.
One of the most serious problems faced by instant tea manufacturers is that the tea powder prepared according to traditional methods, when reconstituted tends to lose the characteristic flavour and aroma of fresh black tea. The reconstituted tea reacts badly to milk and tends to take a dull coloration. The characteristic aroma associated with black tea is lost during various stages of processing. Ideally, hot water soluble instant tea should resemble black tea infusion to the extent possible. However, little amount of cloudiness and haze could be present in the tea.
However, the prior art does not yet provide a cost effective and simple method for the production of instant hot tea. And, it is desirable to provide an instant tea product, which when reconstituted in hot water retains characteristic aroma and other organoleptic properties of tea.
The applicant's studies have shown that the water used for tea extraction plays a crucial role, especially in the stage prior to stripping the black tea extract of its aroma and prior to reconstitution. The Applicant has found that the process must be modified and similarly, before the volatile aroma constituents are incorporated into the tea extract, they must be processed.